SMA Solar Inverters 501 error code

This post is specifically for people who encounter a 501 error code / event message on their SMA Sunny Boy series inverter.

So, you finished hooking up your panels, got the inverters installed, and checked your AC side connections and turned on your inverter to see a 501 error code, which is defined as a grid fault wherein the power frequency is outside of the inverter's range. Frequency refers to the Hertz range that your utility company uses, and here in the U.S. it is 60. The Sunny Boy series inverters will allow at minimum 59.3 Hz and at maximum 60.5 Hz. So what is the problem?

Reading the error code's definition would lead you to believe there is a problem with the utility grid's frequency, as it did for me, since you probably haven't attempted to connect to the inverter's software using your phone or laptop. I called the power company and asked them to check the grid frequency, which of course was within the inverter's range of acceptable frequency. Now what?

You call SMA's customer service number, wait on hold for an hour or two depending on how many other people are having trouble with their inverters, and you finally get a tech. He'll tell you that the error code means exactly what it says, and ask you what the frequency is on the grid. What he isn't telling you is that in the U.S. most power companies don't control the frequency; it is almost always synced to a larger grid.

When I called, bless his little heart (southern for "He's a moron"), the tech said there is no other reason it would give that error code. Well, son, there sure is. Honestly, it's a stupid mistake and one that you'll kick yourself for, but it's an easy fix.

When we connected the AC side of the inverter to the AC disconnects, and on down the line to the electrical panels, we installed standard wiring for a basic 240 volt input: 2 hot leads and a ground. We were missing the neutral wire to complete the 240 volt split phase install we actually needed. We ran the fourth wire and two of the inverters came to life, but two still read a 501 error code. Hmmm.

I had updated two of the inverters (the two still throwing the code) and when I went into the installer login and checked the settings it wasn't displaying a country code. I kept going to the default setting, as a video I watched from SMA solar said it was the standard setting most everyone would use. Nothing. Then it dawned on me... and I hate even admitting this.

I turned it off, and turned it back on again.

I had to detach the DC inputs and isolate the inverters using the disconnects so they would have no access to power, waited the required five minutes for the system to completely reset, and when I turned them back on they began generating power. It's that easy. The inverters had adopted the new country code setting, and after cycling through the startup screens it began generating solar power.

If you got the 501 error code / event message then try what I did; I can't guarantee it will work for everyone, but for some reason the tech didn't even consider this as an option. Good luck on your solar installs; I now have one complete install under my belt and look forward to my next one.

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